Tailoring the ratios between eigenfrequencies of tapping mode atomic force microscope probe using concentrated masses

Higher harmonics signal in tapping mode atomic force microscope (AFM) topography imaging process is verified to be an evidence for material mapping in sample surface. Due to low amplitude and rapid decay of higher harmonics, structure design focused on cantilever probe is proposed to optimize the frequency response performance of probe. Here, we utilize concentrated masses to tune the ratio between eigenfrequencies for tip attached probe. Euler-Bernoulli beam theory is the fundamental for analysis. We figure out that adding masses can realize the tailoring of eigenfrequency ratios, and two concentrated masses will produce more frequency combination candidates than one concentrated mass. Probe with integer ratios between eigenfrequencies generates high sensitive responses at corresponding higher harmonics.